Immigration was the hot-button issue at the Republican presidential YouTube debate Wednesday night as GOP presidential contenders accused each other of hiring undocumented workers and providing them sanctuary. Meanwhile, new analysis reveals that immigration over the past seven years has experienced its highest surge in the nation's history.

At the debate, Rudy Giuliani and Mitt Romney threw the first blows, accusing each other of harboring and hiring undocumented workers. Romney accused Giuliani, the former mayor of New York City, of creating a "sanctuary city" of undocumented workers. Giuliani responded, saying that Romney hired undocumented workers to work on his house when he was governor of Massachusetts. (See also: How Would Your Presidential Candidate Vote on Immigration?)

"I would say he had [a] sanctuary mansion, not just [a] sanctuary city," said Giuliani when referring to Romney, reports The New York Times.

This and other heated exchanges among the candidates last night show that immigration is this election season's third-rail topic. It's an issue on which each candidate has a spotty record, regardless of whether they support or oppose a path to citizenship--and on which our government has yet to find a comprehensive solution.

Meanwhile, the number of immigrants entering the country continues to rise.

(See also: How Does Your State Measure Up on Immigration?)

Since 2000, 10.3 million new immigrants have entered the country. That is the highest rate of immigration for any seven-year period in the country's history and more than half of the new immigrants were undocumented workers, according to research conducted by the Center for Immigration Studies (CIS), reports The New York Times.

See Figure 1 to see just how much immigration has increased over the last decade.

CIS, which advocates reduced immigration rates, reports that 37.9 million people, or one in eight people living in the United States, are new immigrants.

Other findings included the following:

• 11.3 million immigrants are undocumented workers
• About 30 percent of all immigrants and their children lack health insurance, compared with 13 percent of people born in the United States
• One in three people without health insurance is an immigrant or a U.S.-born child who has at least one immigrant parent
• Immigrant families account for almost 75 percent of the increase in the uninsured in the past 15 years
• About one-third of immigrant families receive some kind of public assistance, such as food stamps and Medicaid for their children who were born in the U.S. Most children in immigrant families, regardless of the parents' legal status, were born in the United States
• About 31 percent of documented immigrants and undocumented workers who are older than 25 do not have a high-school diploma, while 8.4 percent of U.S. citizens don't have a high-school diploma

CIS' research did not show that immigrants are using public services at higher rates than U.S.-born citizens, reports The New York Times.

(See also: Hoax Alert! Undocumented Immigrants Do NOT Get Social-Security Benefits)

Wayne Cornelius, a political-science professor at the University of California, San Diego, who has studied Mexican immigration for decades, told The New York Times that the study's conclusions about immigrants' use of public services is "misleading."

"They are less likely to have health insurance, but they are also less likely to seek medical attention," Cornelius told The New York Times.

Another critic, Dowell Myers, a demographer at the University of Southern California, found fault with the CIS study because it does not profile immigrants' contributions.

"This is a one-eyed portrait," Myers told the times Times. "It is a profile of immigrants' dependency without any profile of their contributions."

Myers' research shows that within 10 years, new immigrants to California found jobs with health and other benefits, causing the rate of uninsured immigrants to drop.

Read the September 2007 issue of DiversityInc magazine to learn more about the business case for immigration.

(See also: National Latino Groups Say 'We Must Start Anew') 

More Election '08 >>